Seal for sectional leading-in wires.



J. T. FAGAN.

SEAL FOB SECTIONAL LEADING-IN WIRES. APPLICATION FILED 0M. 11, 1907.

1,032,476. Patented July 16, 1912.

6 71 B fi D7 lira. L9.

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QWKLM JOHN T. FAGAN', or CLEVELAND, or-rro.

SEAL FOR SECTIONAL LEADING-IN WIRES.

Specification of Letters ratent.

Patented July 116, 1912.-

Application filed October 11, 1907. Serial No. 396,889.

To all whom it may concern:

Be'it known that 1, JOHN T. FAGAN, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Seals for Seetional Leading-In Wires, of which the following is a fullfclear, and exactdescription.

The object of the present invention is to provide an improved form of sectional leading-in wire for incandescent lamps, in which the sections shall have their joints, or what are commonly called knots, of such diameter as to notendanger the effectiveness of the seal. i

It is the purpose of my invention to provide electric lamps and other articles, in which sectional leading-in wires may be advantageously employed, with a seal in which the glass covering over the joints is of substantially the same thickness as the covering over the larger conducting wires, for which latter covering the jaws of the machine are gaged,

Referring to the accompanying drawings as illustrating certain embodiments of my invention, Figure 1 is an elevation showing an end of the copper conductor with the end of a platinum section placed in position relatively thereto to form the knot. Fig. 2 is a cross section taken on the line 2-2 of Fig. 1. Fig. 3 is a plan view taken as looking down on Fig. 1. Fig. 4 is a side elevation showing the joint between the copper and the platinum sections after the fusion has taken place. Fig. 5 is a cross section taken on the line 55 of Fig. 4. Fig. 6 is a plan View looking down on Fig. 4. Fig. 7 is a cross section showing the particular form of copper wire illustrated in Figs. 1, 3, 4: and 6, the line of section being indicated by the lines 77 of these figures. Fig. 8 is a cross section of a, modified form of copper wire, which may be used in forming'the seal according to my present invention. Fig. 9 is a cross section of still another modification of copperwire capable of being used for this purpose; and Fig. 10 is a detail cross section showing the joint embedded in the glass seal.

In the various forms shown I have'provideda conducting wire A 'of copper, or equivalent material, which is provided with a groove, channel, recess or cavity, such as B,-B or B into which may be placed the end of a platinum section 0. In forming the joint, the groove, channel, recess or cavityv which I provide in the conducting wire may extend the full length of the wire, or be merely local, as the economy of manufacture may dictate,-it being essential that this groove, channel, recess or cavity be located at the point of formation of the knot or joint.

In forming the joint, the end of the platinum section C'is placed within the recess provided in the conducting wire, a sufficient length, and only a suflicient length, of the platinum being placed therein to form the joint successfully, and a fusing flame or are is then directed onto the copper wire at the zone of the joint. Now, it is well known to those skilled in such matters that if the platinum wire were merely resting against a flat or convex surface of the copper wire, while the latter was being fused, the surface tension and-tenacity of the skin of the copper beadwouldbe sufficient to support the platinum which would, as the bead expanded, merely reston the surface thereof without being enveloped by the fused copper. Further, inasmuch as there is no' capillary attraction between metal platinum and fused copper, the contact surface between the platinum section and the copper head would be exceedingly small, and a joint cannot be made in this manner. By the method which I have devised, however, of providing the conducting wire with a previously prepared groove, channel, recess or cavity of such contour, and proportion that the copper mass will partially envelop -the platinum sect-ion, when placed therein, the enveloping being of such extent that the fusing and spreading copper at the edges of the groove, channel, recess or cavity will surround and inclose the platinum section with suflicient certainty and quickness to overcome the resistance of the surface tension ofthe fused conducting wire, which tends to hold the platinum section away from the center of the conductor wire. The effectiveness of this formation is due to, the fact that the platinum wire is partially enveloped by the copper so that the expanded fused copper presses upon the sides of the platinum in such. direction as to cause the flowing copper to swell thereover and embed the platinum in its mass; and also to the factthat the mass of copper atthe edges of the groove,

channel, recess or cavity is ordinarily of reduced thickness of mass, and presents a greater surface to the heat so that it fuses more readily than the copper in the center of the wire, and therefore has opportunity to envelop the platinum sufiiciently to hold it, before the copper immediately beneath the platinum bcomes'fused and expanded sufiiciently to-liftthe latter away from the,

center of the mass. Obviously, by this method I am enabled to produce a joint in which there is no formation of an enlarged copper bead and no displacement of. the fused copper by the thrusting in of the platinum, and, consequently, no projecting enlargements or prongs which would endanger the effectiveness of the seal. The joint formedremains of substantially the same diameter as that of the body of the conducting wire, the cavity or groove being merely filled in. N 0 expansion of moment, accidental or otherwise, exists, and the fused glass of the seal may be pressed to the predetermined thinness by the jaws of the seal-forming machine Without fear of the glass covering at'the seal being thinner over the joint than over the. body of the conducting wire. The thickness of the cover over the body of the conducting wire is, of course, quite sufficient for the purpose of forming an elficient seal, and there will be no danger of the glass cover, when of this thickness, being cracked by reason of undue expansion, in any direction, of the joint.

Having described my invention, I claim: A sectional leading-in wire constituting the embedded electrical conductor passing through thevitreous seals of incandescent lamps, comprising sections of longitudinally alined dissimilar metals ha\ ing overlapping ends forming a fused oint one of said sections, having the smaller diameter, being of 'a material Whose coefiicient'of expansion is substantially the same as that of glass, the

other section being of more fusible metal at all points-of its periphery, the joint being of the same diameter as the larger section.

In testimony whereof, I hereunto ailix my signature in the presence of two witnesses.

- JOHN T, FAGAN. Witnesses:

F. P. HARRIS, C. O. GALE. 

